Montana's Spanish Oro y Plata was conceived as the Montanans were deciding on an official seal for the new Montana Territory. In 1865, shortly after Montana had gained territorial status, a committee, chaired by Mr. Francis R. Thompson, got together to determine an appropriate design for the new seal. The committee agreed that the seal should incorporate certain essential elements of Montana's economy and its future.
As the committee discussed the new seal the question of a territorial motto was introduced. Based on the mineral wealth that Montana had produced since 1862, members favored "Gold and Silver" as a meaningful motto for Montana Territory. Someone thought the motto would have a nice ring in Spanish and, again, there was agreement. Seal design and motto were presented to the Legislature on February 4, 1865. At this time there was a suggestion that "El Dorado," meaning "the place of gold," might be more appropriate than simply "Gold and Silver." But both Montana houses approved the seal with the motto 'Oro y Plata' and Territorial Governor Sidney Edgerton signed the bill into law on February 9, 1865.
There are two states with mottos that focus on minerals and wealth:
The law designating the official Montana state motto is found in the Montana Montana Code Annotated, Title 1, Chapter 1, Part 5, Section 1-1-501.
This statute describes the Montana seal. The motto is specified within this description.
TITLE 1. GENERAL LAWS AND DEFINITIONS.
CHAPTER 1. GENERAL PROVISIONS.
Part 5. State Symbols - Official Designations.
SECTION 1-1-501.
1-1-501. Great seal. The great seal of the state is as follows: a central group representing a plow and a miner's pick and shovel; upon the right,
a representation of the Great Falls of the Missouri River; upon the left, mountain scenery; and underneath, the words "Oro y Plata". The
seal must be 2 1/2 inches in diameter and surrounded by these words, "The Great Seal of the State of Montana"
History: En. Sec. 1, p. 42, L. 1893; re-en. Sec. 1130, Pol. C. 1895; re-en. Sec. 430, Rev. C. 1907; re-en. Sec. 526, R.C.M. 1921; re-en. Sec. 526,
R.C.M. 1935; R.C.M. 1947, 19-111.